Right on Neb86. When that throttle opens up quickly and the accelerator pump shoots a big shot of cold wet gasoline and a gob of fresh cold air into that violent turbulent environment it takes a huge amout of voltage to ionize the spark plug gap. Much more so than the relatively peaceful combustion chamber at idle. Within it's design limits, the coil will put out whatever voltage it must to find a path to ground.

Terrier's first step should be to take a reading on his spark plugs. But he has probably fixed his problem by now.

 

HI all

Well I made a classic mistake, did two things which made some improvement, but don't know which one made the difference!!

I am still going to change plugs etc today, but yesterday when I had a few mins, i removed the distributor cap cleaned it up along with the rotor then i used some carb cleaner sprayed directly into the carb.


There is an improvement, however still running a bit rough and missing when warm.

With regards to the fast idle, should i adjust it and if so what is the recommended level? also where is the adjustment screw?

I will continue to work through the suggestions above, and will keep you updated.

Thanks again for all the advice and suggestions.

Erl

 

Terrier,

From your first post, it sounds like the fast idle is close to what it should be, but check the specs. The fact that the "fast idle" remains operational after the engine warms up makes me think that the fast idle cam is not returning when the choke opens, or the choke is NOT opening. If you determine that the choke butterfly IS opening then examine the linkage. But first, get a can of carb cleaner and spray the linkage so that it is clean so you can figure out how it all works. Get a good light source in place so that you can see clearly. Manually open and close the choke and look for a stepped cam that is moved by the choke linkage. When closed, the fast idle cam is rotated up so that an idle speed adjusting screw contacts one of the steps. When the choke plate is open, that fast idle cam should drop (from gravity and/or a small spring,) so that it no longer contacts the adjustment screw. At that time the idle will be set by the normal idle speed screw. What I am thinking is that there is something that is preventing that fast idle cam from returning. Disengaging.

All that only has to do with the idle speed, let us know what happens after the new ignition parts are in place.